1) THE HUSBAND WHO RETURNED HOME BY UTTERING "THE NAME"
QUESTION: The Gemara cites a Beraisa which states that if a man says to his wife, "This is your Get on condition that you go up to the sky," the Get is invalid. TOSFOS (DH Al Menas) writes that the text of the Beraisa in Bava Metzia (94a) is that if the condition is fulfilled the Get is valid. Tosfos asks how it is possible for the woman to fulfill the condition (before the era of aviation) to go up to the sky. Tosfos answers that it is possible to go up to the sky by uttering the "Shem," the Divine Name of Hash-m.
What is the source that wonders performed by uttering Hash-m's Name have binding validity in Halachah?
ANSWER: The Gemara later (89a) cites a Beraisa which states "Mamzeres Ein Chosheshin Lah." RASHI (DH Mamzeres) explains that if a rumor goes out that a woman is illegitimate, no significance is given to the rumor and the woman remains of kosher lineage.
The ROSH (Kidushin 4:7) cites the BA'AL HA'HALACHOS who explains that even in a scenario where the husband went overseas and his wife had a baby which it would seem logically could not have been fathered by the husband, nevertheless the baby is kosher, because we say that the husband came home secretly by reciting the Shem and thereby arriving immediately from a great distance, and the baby was born from the husband and therefore is not a Mamzer.
The Rosh also cites the Yerushalmi (also quoted by Tosfos to Kidushin 73a, DH Mai) which relates that Shmuel in fact was born in such a way; his father (Avuha d'Shmuel) went overseas and came home by reciting the Shem, Shmuel's mother conceived as a result.
This possibility is also mentioned by the SHULCHAN ARUCH (EH 4:14). The Shulchan Aruch rules that if a woman's husband went overseas and remained there for more than twelve months and she gave birth after twelve months, the law is that the baby is a Mamzer because it is not possible that a pregnancy could last for more than twelve months. The Shulchan Aruch adds that there is an opinion that the baby is not a Mamzer, and he concludes that since there is a dispute the baby has the status of a Safek Mamzer.
The BEIS SHMUEL (#16) writes that the second opinion cited by the Shulchan Aruch is that of the Ba'al ha'Halachos. The Beis Shmuel writes that this does not contradict the Halachah (see Shulchan Aruch EH 143:12) that if a husband gives his wife a Get on condition that she flies up into the sky, the condition is not valid and the Get takes effect. In that case, the possibility of flying up to the sky by saying the Shem is not considered a serious possibility, and therefore the Get is considered to be unconditional and takes effect immediately. In contrast, to prevent a child from being classified as a Mamzer, the possibility that the husband came home through the use of the Shem is taken into consideration. Wherever possible, a way is always sought to prevent a child from having the status of a Mamzer.
The CHELKAS MECHOKEK (EH 4:8) writes that even according to the first opinion in the Shulchan Aruch, if the woman claims that the husband came home during the twelve months (as opposed to arguing that her pregnancy lasted more than twelve months) and the husband agrees, there is no doubt that the baby is legitimate (as in the case of Shmuel).
The Chelkas Mechokek adds that even if the husband is not present and the woman argues that he came home through the use of the Shem, it is possible that she is believed, as long as the husband does not contradict her, because of her Chazakah that she did not commit a transgression. However, the Chelkas Mechokek also writes that it is possible that the wife is not believed on her own to make such an unusual claim and say that the husband arrived home through the use of the Shem. (D. Bloom)

84b----------------------------------------84b

2) CONDITIONS BEFORE AND AFTER THE CRUCIAL PART OF THE GET
OPINIONS: The Mishnah (82a) states that according to the Chachamim, one who gives a Get to his wife and says to her, "You are permitted to marry everyone except a certain man," the Get is invalid. The Mishnah concludes that even if he erases this condition from the Get afterwards, the Get remains invalid.
The Gemara (84b) quotes Rava who explains that although the Mishnah invalidates a Get only when the disqualifying condition is written in the Get but not when the husband merely spoke the condition orally, the Mishnah's ruling applies only to conditions which were said after the Toref was written. (See, however, Rashi DH Kasvu, who implies that even with such conditions, the husband must say at the time he hands over the Get, "You are permitted to everyone.") (Rashi there (DH Kasvu) explains the Sugya according to Rav Safra who says that the Get is valid. One nevertheless may infer from Rashi's words the reasoning of Rava who disagrees with Rav Safra and invalidates the Get.)
(See also Rashi to 21b, DH Toref, who writes that the Toref is the "Giluy" of the Get, the part which "exposes" its main purpose -- the mention of the name of the husband, the wife, and the date. See also BEIS SHMUEL (EH 123:6) in the name of the BEIS YOSEF who explains why the date is considered so important even though the requirement to write the date is only mid'Rabanan.)
However, a condition which is stated before the Toref is written invalidates the Get even though it is not written in the Get. This is because the Toref is the crucial part of the Get, and since the crucial part of the Get is written with the invalid condition, the Get is invalid. (See RASHI DH Afilu.)
The Gemara says that Rava's opinion is consistent with his own practice. Rava used to tell people who wrote Gitin, "Make sure that the husband keeps quiet until you write the Toref of the Get."
(a) RASHI (DH Shetuki) explains that Rava told the people to admonish the husband not to mention any conditions in the Get. TOSFOS (DH Shetuki) also writes that Rava refers to all conditions (of "Al Menas") written in a Get before the Toref and not only to the condition mentioned in the Mishnah ("Chutz"). Tosfos adds that Rava is consistent with his opinion later in the Sugya where he maintains that any condition of "Al Menas" before the Toref may not be made, lest the husband write the condition of "Chutz" before the Toref, which is invalid according to the strict letter of the law.
The RAMBAM (Hilchos Gerushin 8:4) also writes that even if the husband speaks a condition of "Al Menas" orally before the Toref is written, the Get is invalid.
The Gemara cites a Beraisa which states that according to Rebbi, all conditions render a Get invalid, while according to the Chachamim only conditions which invalidate a Get when spoken orally invalidate it when written. Therefore, "Chutz" is invalid both orally and in writing, while "Al Menas" is invalid neither orally nor in writing.
Rava later (85a) states that the dispute between Rebbi and the Chachamim applies only to conditions made after the Toref, while everyone agrees that any condition made before the Toref is invalid. Rava states that when the Mishnah refers to written conditions (which the Gemara (82a) explains is a reference to the Tenai of "Chutz" but not conditions of "Al Menas"), it refers to conditions made after the Toref.
(b) TOSFOS (85a, DH Aval) writes that the reason why even a condition of "Al Menas" written before the Toref is invalid is due to a Gezeirah that one not make a condition of "Al Menas" even orally, lest one make a condition of "Chutz" which is completely invalid (and not only because of a Gezeirah) even when made orally (because, according to Rava, a condition of "Chutz" made even orally ruins the necessary "Kerisus," severance, element of the Get).
The RAN and RABEINU KRESKAS question the view of Rashi and Tosfos. They ask that if a condition of "Chutz" before the Toref invalidates a Get mid'Oraisa even when it is made orally, why did the Chachamim not enact a Gezeirah for a condition of "Chutz" made orally after the Toref, lest one orally make a condition of "Chutz" before the Toref (similar to the Gezeirah enacted for one who writes a condition after the Toref, lest he write a condition before the Toref)?
(c) A number of Rishonim (RAMBAN in Chidushim and Milchamos, RAN, RABEINU KRESKAS, and others) learn the Sugya differently from Rashi and Tosfos. They understand that even a condition of "Chutz" -- which invalidates a Get when made orally before the Toref -- invalidates the Get only because of a Gezeirah lest one write the condition in the get before the Toref. Accordingly, a condition of "Al Menas" is valid when stated orally even before the Toref, because the Chachamim did not make a Gezeirah for a Gezeirah. The reason why Rava commanded to keep the husband quiet was so that he not mention a condition of "Chutz."
(e) The RITVA (manuscript, printed by Mosad ha'Rav Kook) explains that a condition written in the Get constitutes a strong, binding act. The TORAS ABIRIM explains that a Gezeirah was enacted for a written condition after the Toref so that one not come to make a written condition before the Toref. Orally-made conditions, in contrast, are weaker, and thus the Chachamim enacted no Gezeirah for an oral condition made after the Toref because of a condition made before the Toref; those two conditions will not become confused. (See also MAHARSHA to TOSFOS DH Shetuki.) (D. Bloom)